Diagnostic clinical analyzers continue to become more sophisticated especially with respect to the handling and movement of patient samples and associated reagents between multiple locations. A plethora of increasing complex pick and place transports have evolved into robotic systems capable of two-dimensional, and in some cases, three-dimensional movement of patient sample containers. However, the evolution of apparatuses to physically acquire and hold such containers has not advanced especially when such containers are not simple test tubes, such as, for example, foil sealed cassettes for agglutination reactions as shown in U.S. Pat. No. 5,780,248 incorporated herein by reference in its entirety. Furthermore, such patient sample container acquisition relies upon a small number of fundamental mechanisms. Cam driven machines offer the smoothest motion and control of acceleration and deceleration. They can run at high cyclic rate, however, they are big, heavy and not suitable for applications where space is limited. Hydraulic/pneumatic driven machines are more compact and easier to use, but because they usually use hydraulic/pneumatic pressure to drive the components against hard stops, they create impact (which is particularly important in handling cassettes containing whole blood components) and result in noisy machines of low cyclic rate. Servo motor/stepper motor driven machines are usually slower, can be higher in cost, but have more flexible operation. U.S. Pat. No. 5,681,530 relates to a transport system for fluid analysis instruments that includes a cassette gripper and conveyor, incorporated herein by reference in its entirety.
With respect to acquisition of the patient sample container, existing mechanisms tend to be specific to test tubes and are mechanically complex with many parts. In addition to having very limited capability to acquire and hold misplaced patient sample containers because of a limited motion function, these units are expensive to manufacture and often have reduced reliability. Furthermore, most mechanisms impart significant inertial forces to the patient sample container which is very undesirable and potentially can result in altering the sample's physical properties. A number of these systems are noted as follows: U.S. Pat. No. 4,002,247 entitled “Machine for picking up, transferring, turning and placing parts,” U.S. Pat. No. 4,411,576 entitled “Pick and place mechanism,” U.S. Pat. No. 4,975,018 entitled “Linear unit for transferring objects,” U.S. Pat. No. 5,249,663 entitled “Apparatus to load workpieces,” U.S. Pat. No. 5,333,720 entitled “Apparatus to manipulate workpieces,” U.S. Pat. No. 5,467,864 entitled “Dual purpose apparatus to manipulate workpieces,” U.S. Pat. No. 5,564,888 entitled “Pick and place machine,” U.S. Pat. No. 6,264,419 entitled “Robot arm,” U.S. Pat. No. 6,293,750 entitled “Robotics for transporting containers and objects within an automated analytical instrument and service tool for servicing robotics,” U.S. Pat. No. 6,374,982 entitled “Robotics for transporting containers and objects within an automated analytical instrument and service tool for servicing robotics,” U.S. Pat. No. 6,843,357 entitled “Two-axis robot for specimen transfer,” U.S. Pat. No. 6,889,119 entitled “Robotic device for loading laboratory instruments,” U.S. Pat. No. 7,131,361 entitled “Workpiece-transfer device,” U.S. Pat. No. 7,448,294 entitled “Robotic devices,” U.S. Pat. No. 7,563,067 entitled “Robot,” PCT Publication No. WO2008067847 entitled “Container transfer apparatus with automatic positioning compensation,” and U.S. Publication No. 2010/0150688 entitled “Workpiece transfer system.”
None of the prior references noted above disclose an apparatus capable of operating in a confined space, having a minimal number of parts, having the ability to acquire patient samples in cassettes with significant misalignment, and imparting a movement of the apparatus particularity conducive to the acquisition and holding of non-test tube-shaped patient sample containers.